Patients with epidermal growth factor receptor (EGFR) mutations, typically in exons 19 and 21, show dramatic responses to specific tyrosine kinase inhibitors (TKIs) such as gefitinib, erlotinib, afatinib, and osimertinib (10–15% of NSCLC) [1,2]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.